Two wheel trailer dolly



April 1, 1958 o. o.-B| AcKMAN 2,828,973

Two WHEEL TRAILER DOLLY Filed March 30, 1955 2 Sheets-SheelI l April l,1958 o. o. BLACKMAN y 2,828,973

Two WHEEL TRAILER DoLLY 2 Sheets-Sheet 2 Filed March .'50, 1955 9 L@ a 44 5&5.: f S Hd. a f l v f, 0 m,

@JZ/0 www/ 77 6 l 5f 2 7 s; E z a 2 z w W 'IIIIIIIII IIIIII'IIA vINVENTOR .O.BZa 0fma/TL ATTORNEY United States Patent TWO WHEEL TRAILERDOLLY Oddes 0. Blackman, Zwolle, La..

Application March 30, 1955, Serial No. 497,917

6 Claims. (Cl. 280-476) This invention relates to a dolly for two wheeltrailers and has for its primary object to provide a dolly unit capableof being readily attached to a tongue portion of a. two wheel trailer toprovide a resilient support for the forward end of the trailer and whichwill effectively function to relieve a draft vehicle from the weight ofthe forward end of the trailer and which will additionally provide aparking stand to support the front end of the trailer when uncoupled.

Another object of the invention is to provide a dolly unit having areadily adjustable spring suspension system capable of being manuallyadjusted easily for raising or lowering the draft tongue of the trailerto enable the coupling part of the tongue to bedisposed at a properlevel to be readily coupled with or uncoupled from a coupling part of adraft vehicle irrespective of the elevation thereof. f

A further object of the invention is to provide a dolly unit including acaster wheel which is yieldably disposed beneath a trailer tongue toenable it to readily pass over obstructions, which will not interferewith guiding the trailer while being backed, and which is capable ofsupporting the forward end of the trailer while the vtrailer is beingmoved rearward.

Still another object of the invention is to provide a dolly capable ofbeing readily mounted on existing two wheel trailers.

Various other objects and advantages of the invention will hereinafterbecome more fully apparent from the following description of thedrawings, illustrating a presently preferred embodiment thereof, andwherein:

Figure l is a side elevational View showing the dolly applied to theforward part of a two Wheel trailer;

Figure 2 is a horizontal sectional view thereof, taken substantiallyalong a plane as indicated by the line 2-2 of Figure 1;

Figure 3 is an .enlarged fragmentary vertical sectional View, takensubstantially along a plane as indicated by the line 3-3 of Figure 2; f

Figures 4 and 5 are enlarged fragmentary detail cross sectional viewstaken substantially along planes as indicated by the lines 4-4 and 5*-5,respectively, of Figures l and 2;

Figure 6 is a detail cross sectional view, taken substanice f Ward endof the tongue 12 and are suitably secured togather, as by means ofwelding, as seen lat 17.

The front end supporting dolly lll includes a frame, designatedgenerally 18, which tapers longitudinally from its rear toward itsforward endV and which includes a n bottom 19, forwardly converging sidewalls and a top tially along a plane as indicated by the line 6-6 ofFigure 3, and

Figure 7 is an enlarged, substantially horizontal sectional view, takensubstantially along a plane as indicated by the line 7 7 of Figure 1.

Referring more speciiically to the drawings, the trailer dolly in itsentirety and comprising the invention is designated generally 10. Toillustrate a preferred application and use of the trailer dolly 10, theforward part of a two wheel trailer 11 has been illustrated in thedrawings, Said trailer 11 being .of a conventional construction havingits -two ground engaging wheels, not shown, disposed in transversealignment and rearwardly of the balance point of the trailer 11, so thatthe forward. .end

wall 21. The top wall 21 extends from adjacent the forward end of theframe 18 and terminates approximate- .ly intermediate of the ends ofsaid frame, as best seen in Figure 3. A kingpin 22 extends through thebottom wall 19 and top wall 21, adjacent the forward end of the frame18, and is disposed with its axis at a right angle to the longitudinalaxis of said frame. The kingpin 22 is secured immovably to the frame 18,as by welding, as seen at 23. A boss 24 is secured to the underside ofthe bottom 19 and is disposed around the kingpin 22. A bearing 25 issecured as by additional welding as'seen at 23 to the underside of theforward end of the `bottom 19 and to a forward part of the boss 24 andis disposed crosswise of the frame 18. As best seen in Figure 6, a pairof bearings or bushings 26 are secured in transverse alignment with oneanother, as by additional welding 23, to portions of the bottom .edgesof the vertical flanges 15 of the tongue members 13y and 14. Thebearings 25 ts turnably between the bushings 26 and a pin or axle 27extends through the bearing 25 and bushings 26 and provides a journalfor said bearing, whereby the frame 18 is mounted for swinging movementvertically in the tongue 12. The pin or axle 27 can be secured byfastenings 2S to one or both of the bushings 26.

A sleeve 29 extends through and is suitably secured in a plate 30. Thesleeve 29 is disposed with its axis at an oblique angle to the plane ofthe plate 3f). The sleeve 29 swivelly engages the knigpin 22, below theboss 24, and is retained applied thereto in any suitable manner as bymeans of a Cotter' pin 31, which extends through the kingpin 22,adjacent its lower end and beneath the sleeve 29, as best seen inFigures 3 and 4. A thrust washer 32 is preferably mounted on the kingpin22 Ibetween the boss 24 and the upperend of the sleeve 29. A pair ofbars 33 have corresponding ends disposed on the plate St). Each of saidbar ends is secured to the plate 30 by a nut and bolt fastening 34 andby a U bolt and nut fastening 35, to prevent the bars 33 from sliding orswinging relatively to the plate 30. The bars 33 are secured to theplate 3i) near itslside edges and project from the lower edge thereof,as seen in Figure 1. The'sleeve 29 is disposed intermediate of the sideedges of the plate 3h and near its upper edge. The bars 33 are disposedsubstantially parallel to one anotherr and combine with the plate 30 andsleeve 29 to form a caster wheel fork. The Ibars 33, near their lowerfree ends, have bearings 36 secured thereto and which are disposed inalignment to receive end portions of a wheel axle 37, which extendsthrough and provides a journal for a wheel 3S, which is thus jcurnaledin the wheel fork 3l), 33. The Ywheel 38 isV preferably equipped with apneumatic tire 39.

The frame 18 extends rearwardly from its pivot 27 and is of a width toiit swingably between the tongue portions 13 and 14, as best seen inFigures 2 and 5. A yoke 40 is disposed over the rear end of the frame 18and has `depending legs the terminal portions 41 of which looselystraddle portions of the tongue parts 13 and 14 and are pivotallyconnected thereto by nut and bolt fastenings 42 which.extend through theflanges 15 thereof and loosely through said leg portions 41. The yokehas a substantially at horizontal top portion 43 provided with anopening 44, and which is disposed substantially above the level of thetongue 12. An internally threaded boss 45 is mounted on andsuitablysecured to the top portion 43. A screw 46 extends threadedly through theboss 45 and loosely through the opening 44. A relatively heavy coilspring 47 has a lower end disposed in the rear portion of the frame 18and suitably secured to the frame bottom 19. The spring 47 `extends.upwardly from the rear end of the frame 1e'- within the yoke 40 and theupper end thereof is suitably secured to an outer lsection 48 of abearing 49. The bearing 49 has an inner section 50 swivelly mounted inthe outer'scction 48 and to which the lower end of the screw 46 `isconnected. An elongated handle 51 extends transversely' through and maybe removably mounted in the screw 46, adjacent the upper end thereof andis adapted to be manually engaged for turning the screw 46 in eitherdirection.

A bar 52 is secured by nut and bolt fastenings 53 to the rear endportion of the top wall 21 and is disposed transversely thereof andsubstantially to the rear of the frame pivot 27. A strip of cushioningmaterial 54 is secured to the underside of the bar 52 and extendssubstantially from end-to-end thereof. The bar 52 and strip 54 form astop and the ends thereof overlie portions of the top flanges 16 of thetongue parts 13 and 14, as seen in Figure 2, for a purpose that willhereinafter be described.

A sleeve 55 is disposed in the forward end of the tongue 12, between theanges 15 and beneath the flanges 16, and is secured to thc tongue bywelds 17. The sleeve 55 is disposed laxially of the tongue 12 and has aforward end extending slightly beyond the forward end of said tongue. Ashaft or pin 56 extends through and is swivelly disposed in the sleeve5S and is maintained in engagement therewith by thrust collars 57 and58, which are detachably secured to the ends of the pin 56 and whichbear against the ends of the sleeve 55. The forward thrust icollar 58 isprovided with a forwardly projecting extension 59 which terminates in aneye 60. The eye 69 fits loosely in a bifurcated shank end 61 of a forkmember 62 and is pivotally yand detachably connected thereto by a pivotfastening 63 which extends through the bifurcated portion 61 and throughthe eye 60. The fork 62 has forwardly projecting spaced prongs or arms64 which are adapted to loosely straddle a pair of arms 65 of a couplingsection 66. The coupling section 66 comprises a bar from which the arms65 project. for example, on the rear bumper 67 of a vehicle, not shown,such as an automobile, constituting the draft vehicle for the trailer11, and is securedto the outer side of the bumper 67 and intermediate ofits ends by a nut and bolt fastening 68, which extends through the bar,between the arms 65, and through the bumper 67. The bar of the couplersection 66, remote from the arms 65, has a 'laterally turned terminal.portion 69 which is shown engaging under the bottom edge of the bumper67 to yprevent the coupler section 66 from turning relative to thebumper. The arms 65 are thus maintained in vertically spaced relation toone another. Said arms and the fork arms or prongs 64 have registeringopenings, not shown, through which a coupling pin 70 detachablyextendsrfor coupling the trailer `vehicle 11 to the bumper 67. It willbe readily apparent that the coupling pin 7i; provides a pivotpermitting the fork 62 to swing horizontally relative to the couplingsection 66 and the pivot 63 allows the tongue l2to pivot verticallyrelative to the fork 62. Additionally, `the swivel connection of the pinorshaft 56 in the sleeve 55 `permits the collar extension 59 and thefork 62 to swivel relative to the tongue 12 or vice versa, thusproviding a universal connection between the trailer vehicle 11 and thebumper 67.

The swivel engagement of the sleeve 29 with the king- The coupler 66 isadapted to be mounted,

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(i il pin 22 permits the caster wheel fork 30, 33 to revolve through anare of 360 relative to the frame 18. Accordingly, when the trailer 11 isbeing drawn forwardly or from right to left as seen in Figures l and 2,the caster wheel 38 will assume a position as seen in full lines inFigure l and in Figure 2, beneath the tongue 12 and the dolly frame 18and behind the kingpin 22. The tension of the spring 47 can be adjustedby manually turning the screw 46 to either raise or lower the frame 18the wheel fork 30, 33. If necessary,.a plurality of spacing elements orwashers 71, as seen in Figure 3, may be interposed between the top wall21 and the cushioning strip 54 `for elevating the stop 52, 54 relativeto the frame 18 to permit the caster wheel 38 to be swung downwardlyrelative to the tongue 12, below its position of Figure l, where thecoupling part of the draft vehicle is at a higher elevation than asshown in Figure l. It will thus be seen that the unit 10 provides aspring suspension for supporting the weight of the forward end of thetrailer 11 when in transit to remove this weight from the connection ofthe trailer tongue to the draft vehicle, and additionally provides aparking stand when the trailer is uncoupled. Adjustment of the screw 46also enables the fork 62 to be positioned at a proper elevation forcoupling to a draft vehicle thereby eliminating the need for lifting theforward end of the trailer when coupling the trailer to a draft vehicle.

The front end suspension unit or dolly 10 will effectively support theforward end of the trailer 1l while being drawn forwardly. The wheel 38in passing over `high spots on a roadway may yield upwardly relative tothe tongue 12. When this occurs, the frame 18 will swing upwardly in thetongue 12 counterclockwise as seen in Figure l about its pivot 27thereby further compressing the spring 47. After the wheel 38 passesover the high spot, the spring 47 will return the unit to its normalposition. The yoke 40 is swingably mounted by the fastenings 42 on thetongue `12 for swinging movement longitudinally of the tongue. Thus, 'asthe frame 13 is swung upwardly the yoke 40 can swing forwardly so thatthe spring will remain in alignment with the screw 46 and will not belaterally distorted by up and down movement of the frame 18.

The unit 10 will not interfere with backing the trailer 11 while hitchedto a draft vehicle. When the trailer is backed, the fork sleeve 29 willswivel on the kingpin 22 to permit the wheel 38 to assume its dottedline position of Figure l beneath the forward end of the tongue 12 andforwardly of the Kingpin 22. ,The stop 52, 54 will then function toprevent the frame 18 from rocking downwardly below its position ofFigure l and so that the front end of the trailer 1-1 will still besupported by the unit 10.

Various modifications and changes are contemplated and may obviously beresorted to, without departing from the spirit or scope of the inventionas hereinafter defined by the appended claims.

I claim as my invention:

1. A front end dolly for two wheel trailers comprising, in combinationwith a two wheel trailer having a rigid forwardly extending draft tongueincluding a forward end adapted to be coupled to a draft vehicle andprovided with tongue members having laterally spaced portions, anelongated dolly frame loosely disposed between said tongue portions andlongitudinally of the tongue, means pivotally connecting a forward endof the frame to the tongue for up and down swinging movement of theframe relative to the tongue, a kingpin secured to and extendingvertically through the frame near the forward end thereof, a casterWheel fork swivelly connected to the kingpin beneath the `frame andtongue, a ground engaging wheel journaled in said wheel fork, a yokedisposed over a rear end portion of said frame and over a part of thetongue and having end portions straddling parts of said tongue portions,means connecting said yoke to said parts of the tongue portions, aspring stop mounted in the upper part of said yoke, and an expansioncoil spring having a lower end bearing on the rear portion of the frameand an upper end bearing against the spring stop for yieldablysupporting the tongue and the forward part of the trailer on said dollyframe when the wheel fork and wheel are disposed beneath the frame, saidspring extending upwardly from the frame between said tongue portionsand within the yoke.

-2. A front end dolly as in claim 1, and means adjustably mounting saidspring stop in the yoke for adjustment thereof toward and away from thetongue and dolly frame for tensioning said spring for raising andlowering the tongue relative to the dolly frame.

3. A front end dolly as in claim 2, said last mentioned means comprisinga feed screw extending threadedly through the upper portion of the yokeand connected to a part of said spring stop for swivel movement relativeto another part of the spring stop engaged by said spring, said screwbeing adapted to be manually rotated for moving the spring stop towardand away from the dolly frame.

4. A front end dolly as in claim 3, said means connecting the yoke tothe tongue portions constituting pivots on which said yoke is swingablymounted for lengthwise swinging movement relative to the tongue formaintaining the spring in substantially axial alignment with said screw6 in different vadjusted positions of the frame to prevent distortion ofthe spring.

5. A front end dolly as -in claim 1, an abutment means carried by theframe and engaging the tongue to limit downward swinging movement of theframe relative to the tongue for supporting the weight of thetongue andthe forward end of the trailer on the dolly when the wheel and fork areswung to a position forwardly of the kingpin in backing the trailer.

6. A front end dolly as in claim 1, said fork comprising a plate, asleeve extending through and secured in said plate and disposed with itsaxis at an oblique angle to the plane of the plate, said sleeve swivellyengaging the kingpin for supporting said plate at an incline downwardlyand away from the sleeve, and said fork including a pair of fork armsxed to said plate and projecting outwardly from the lower edge thereofand in which said wheel is journalled. Y

References Cited in the file of this patent UNITED STATES PATENTS2,411,009 Slimp Nov. 12, 1946 2,496,515 Boyes Feb. 7, 1950 2,523,210Hedgpeth Sept. 19, 1950 2,534,575 rConley et al. Dec. 19, 1950 2,639,159Milligan et al May 19, 1953

